The present invention relates to an image processing device, an image processing method, and a recording medium for executing authentication of an object, or estimating an attribute or a state of the object, by comparing comparison feature quantities of a part point of the object on an image between a registered image and an input image.
Conventionally, there are face authentication techniques for authenticating an individual person based on a registered facial image. According to a general face authentication technique, first, a subject to be authenticated is photographed, and a face is detected from the photographed image. Next, a part point (a contour point of an inner corner of an eye, an outer corner of an eye, or a mouth) of an organ (eyes, nose, mouth, or the like) of the detected face is specified. Then, an individual person is authenticated, by comparing between a feature quantity of the specified part point in the photographed image (the input image) and a feature quantity of the specified part point in the registered image.
However, since precision of the techniques of specifying a part point is not 100% in some cases, a part point cannot be specified at a correct position. Specifically, while part-point specifying techniques in general can precisely specify a part point of a front facial image and the like, a position of a part point is deviated in some cases, depending on the person, expression of the face, a direction of the face, illumination, or accessory (such as glasses). That is, a part point detected from a registered image and a part point detected from an input image specified are respectively deviated from correct positions in some cases. Accordingly, as shown in FIG. 6, although photographed images are of the same person, a feature quantity of the left corner of the eye in the registered image and a feature quantity of the left corner of the eye in the input image are greatly different in some cases. In this case, since a feature quantity extracted from the input image is different from a feature quantity in the registered image, an authentication device decides that this is not the same person. That is, there is a problem that the authentication is not correctly executed.
The present invention has been made in view of the above problem. An object of the invention is to realize an image processing device, an image processing method, and a recording medium for stably executing precise authentication, even when a part point specified is deviated from a correct position.